Parents can become less sensitive to violence and sex in movies after watching only a few scenes with disturbing content, according to a new study published in Pediatrics that was conducted by researchers at the Annenberg Public Policy Center.

Parents viewed three brief pairs of movie scenes featuring either violent or sexual content. After seeing the first movie clip, the parents thought the minimum age to see a movie with that content should be 16.9 years old on average for violence or 17.2 years old for sex scenes. After watching the sixth and final scene, the parents were more willing to let younger teens see the movies, 13.9 years for violence and 14 years for sex – lowering the minimum age by three years or more.

As they watched more of the movie scenes, the parents also expressed a greater willingness to let their own children see those movies.

“We know these scenes are somewhat disturbing to parents,” said Dan Romer, associate director of the Annenberg Public Policy Center (APPC) and the study’s lead author. “When parents first see them, they say you shouldn’t let someone younger than 17 see them – which is comparable to an R rating. But they get more and more accepting of that content as they’re watching it.”

The study “Parental Desensitization to Violence and Sex in Movies,” will be published in the November 2014 issue of Pediatrics. It was posted online on Oct. 20. The findings were based on an online survey of 1,000 parents who have children from ages 6 to 17. The movie scenes came from popular films targeted at youth (PG-13), rated R (under 17 requires accompanying parent or adult guardian) or unrated in DVD versions.

Violence and sex more common in movies aimed at youth

The study comes as scenes of sex and violence become more prevalent in movies aimed at youth. A 2013 study in Pediatrics from APPC researchers showed that the amount of violence in PG-13 movies tripled in the most popular movies since 1985. That study also found that the amount of gun violence in popular PG-13 movies in 2012 actually exceeded that in popular R-rated movies. Another APPC study in Pediatrics in 2013 found that movie violence was associated with sex and alcohol use as often in PG-13 as R-rated movies.

The current study examined the effects on parents of viewing violence and sex in movies. “As parents become inured to violence and sex in films, they will be less likely to shield their children from such content,” the study said. Other studies have shown that parents are becoming more tolerant of both sex and violence in movies, and desensitization could be one reason why. If children in turn become desensitized, it could reduce their empathy and encourage aggressive responses to conflict, the authors noted.

The possible effect on movie raters

The authors noted that people who rate movies for the Motion Picture Association of America (MPAA), who are themselves parents, could be subject to the same desensitization “and thus more likely to be lenient when it comes to evaluating the appropriateness of such content for children.” The study said this effect could help to explain the “ratings creep” that has allowed more violence into films aimed at youth.

Romer noted that seeing just one movie clip made the parents in the study willing to drop the minimum acceptable age for teens to see a second similar movie by a year – from 17 to 16. Given that, he said, a film rater for the MPAA’s Classification and Rating Administration (CARA) might be willing to change a rating even if a movie was not recut. “You could go from an R to PG-13 just by watching it a second time,” he said.

The study, which took about 20 minutes for each participant to complete, was conducted in January 2014. Among other conclusions, it found that:

The more movies parents had watched previously, the less restrictive they were as they saw additional movie scenes. Parents who had seen 11 or more movies in the last week before taking the survey rated the first movie clip as suitable for viewers 16.6 years old and the final one suitable for viewers 12 years old.

Parents who watched movie clips with violence or sex became more lenient in judging the other type of content as well.

“We were surprised to see the transfer of desensitization,” Romer said. “If the parents saw movie clips with violence, they became more accepting of the sex scenes, and vice-versa.”

The authors suggested that “our entire culture may be undergoing desensitization to violent movies with consequences that remain unknown.” One possible consequence, they said, is a greater acceptance of the use of guns.

In addition to Dan Romer, the study was conducted by Patrick E. Jamieson, of APPC; Brad Bushman of the Ohio State University; Amy Bleakley, An-Li Wang, and Daniel Langleben, all of APPC; and APPC director Kathleen Hall Jamieson.